/*
 * Copyright (C) 2008 ZXing authors
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS"
 * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

package com.zijunlin.Zxing.Demo.view;

import java.util.Collection;
import java.util.HashSet;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

import com.google.zxing.ResultPoint;
import com.zijunlin.Zxing.Demo.R;
import com.zijunlin.Zxing.Demo.camera.CameraManager;

/**
 * This view is overlaid on top of the camera preview. It adds the viewfinder rectangle and partial transparency outside it, as
 * well as the laser scanner animation and result points. �Զ����View������ʱ�м���ʾ��
 */
public final class ViewfinderView extends View {

	private static final int[]		SCANNER_ALPHA	= { 0, 64, 128, 192, 255, 192, 128, 64 };
	private static final long		ANIMATION_DELAY	= 100L;
	private static final int		OPAQUE			= 0xFF;

	private final Paint				paint;
	private Bitmap					resultBitmap;
	private final int				maskColor;
	private final int				resultColor;
	private final int				frameColor;
	private final int				laserColor;
	private final int				resultPointColor;
	private int						scannerAlpha;
	private Collection<ResultPoint>	possibleResultPoints;
	private Collection<ResultPoint>	lastPossibleResultPoints;

	// This constructor is used when the class is built from an XML resource.
	public ViewfinderView(Context context, AttributeSet attrs) {
		super(context, attrs);

		// Initialize these once for performance rather than calling them every time in onDraw().
		paint = new Paint();
		Resources resources = getResources();
		maskColor = resources.getColor(R.color.viewfinder_mask);
		resultColor = resources.getColor(R.color.result_view);
		frameColor = resources.getColor(R.color.viewfinder_frame);
		laserColor = resources.getColor(R.color.viewfinder_laser);
		resultPointColor = resources.getColor(R.color.possible_result_points);
		scannerAlpha = 0;
		possibleResultPoints = new HashSet<ResultPoint>(5);
	}

	@Override
	public void onDraw(Canvas canvas) {
		Rect frame = CameraManager.get().getFramingRect();
		if (frame == null) {
			return;
		}
		int width = canvas.getWidth();
		int height = canvas.getHeight();

		// Draw the exterior (i.e. outside the framing rect) darkened
		paint.setColor(resultBitmap != null ? resultColor : maskColor);
		canvas.drawRect(0, 0, width, frame.top, paint);
		canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint);
		canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1, paint);
		canvas.drawRect(0, frame.bottom + 1, width, height, paint);

		if (resultBitmap != null) {
			// Draw the opaque result bitmap over the scanning rectangle
			paint.setAlpha(OPAQUE);
			canvas.drawBitmap(resultBitmap, frame.left, frame.top, paint);
		} else {

			// Draw a two pixel solid black border inside the framing rect
			paint.setColor(frameColor);
			canvas.drawRect(frame.left, frame.top, frame.right + 1, frame.top + 2, paint);
			canvas.drawRect(frame.left, frame.top + 2, frame.left + 2, frame.bottom - 1, paint);
			canvas.drawRect(frame.right - 1, frame.top, frame.right + 1, frame.bottom - 1, paint);
			canvas.drawRect(frame.left, frame.bottom - 1, frame.right + 1, frame.bottom + 1, paint);

			// Draw a red "laser scanner" line through the middle to show decoding is active
			paint.setColor(laserColor);
			paint.setAlpha(SCANNER_ALPHA[scannerAlpha]);
			scannerAlpha = (scannerAlpha + 1) % SCANNER_ALPHA.length;
			int middle = frame.height() / 2 + frame.top;
			canvas.drawRect(frame.left + 2, middle - 1, frame.right - 1, middle + 2, paint);

			Collection<ResultPoint> currentPossible = possibleResultPoints;
			Collection<ResultPoint> currentLast = lastPossibleResultPoints;
			if (currentPossible.isEmpty()) {
				lastPossibleResultPoints = null;
			} else {
				possibleResultPoints = new HashSet<ResultPoint>(5);
				lastPossibleResultPoints = currentPossible;
				paint.setAlpha(OPAQUE);
				paint.setColor(resultPointColor);
				for (ResultPoint point : currentPossible) {
					canvas.drawCircle(frame.left + point.getX(), frame.top + point.getY(), 6.0f, paint);
				}
			}
			if (currentLast != null) {
				paint.setAlpha(OPAQUE / 2);
				paint.setColor(resultPointColor);
				for (ResultPoint point : currentLast) {
					canvas.drawCircle(frame.left + point.getX(), frame.top + point.getY(), 3.0f, paint);
				}
			}

			// Request another update at the animation interval, but only repaint the laser line,
			// not the entire viewfinder mask.
			postInvalidateDelayed(ANIMATION_DELAY, frame.left, frame.top, frame.right, frame.bottom);
		}
	}

	public void drawViewfinder() {
		resultBitmap = null;
		invalidate();
	}

	/**
	 * Draw a bitmap with the result points highlighted instead of the live scanning display.
	 * 
	 * @param barcode
	 *            An image of the decoded barcode.
	 */
	public void drawResultBitmap(Bitmap barcode) {
		resultBitmap = barcode;
		invalidate();
	}

	public void addPossibleResultPoint(ResultPoint point) {
		possibleResultPoints.add(point);
	}

}
